Abstract: The tensile tests designed by orthogonal test used to test low carbon billet,hot roll armor plate and cold-roll armor plate at room temperature to investigate the influence of tensile rate on mechanical properties have been discussed in this paper. The results showed that tensile test rates are important variable condition which effect on the test results such as tensile strength,non-proportionalty elongation stress,extensibility,constriction of cross sectional area etc. By controlling the tensile rates,the decrease of uncertainry of measuring and the increase of the authenticity and stability of examination can be reached.